Tubular hosiery tensioning device



March 4, 1969 A. MAZZI 3,430,464

TUBULAR HOSIERY TENSIONING DEVICE.

' Filed April 13. 1967 Sheet of 2 as Fig.1

INVENTOR' HRRNIS NHZZ/ WMMM hrronmsys March 4, 1969 MAZZ] 3,430,464

TUBULAR HOSIERY TENSIONING DEVICE Filed April 15. 1967 Sheet 2 of 2 Fig.5

Fig.8

INVENTOR HRRMIS MHZZI BYMM fi RTWRNEYS United States Patent US. Cl. 66153 Int. Cl. D04b /88, 27/34, 35/00 9 Claims ABSTRACT OF THE DISCLOSURE A tubular hosiery tensioning device includes two resilient sleeves which are arranged to engage with their ends the knitted fabric alternately and thereby hold the fabric under tension at all times. In a modification one sleeve merely prevents the fabric from slipping back when the other sleeve is retracted.

This invention relates to tensioning devices for circular knitting machines.

Tensioning devices for a tubular knitted article have been proposed for circular knitting machines for the manufacture of socks and other generally tubular fabrics. Such devices include two assemblies alternately moved in the axial direction and resiliently loaded during the working stroke (that is, in the article advancing direction) to engage and resiliently to tension the fabric, whilst cooperating with a funnel wall along which the fabric article slides.

The members actively engaging the article are relatively complex and also expensive, and the members, in general, include two sets of oscillatory metal elements in order to have the active ends movable in the centripetal and and centrifugal direction. In addition to the complexity and cost, these members also result sometimes to cause difficulties because of the possibility of seizing, owing to binding between lubricant and fibres of the yarn.

Moreover, it is necessary to leave a certain lateral play between one member and the other to allow for the.

contraction of the contact during the active stage and this may cause defects in the article.

According to the present invention there is provided knitted tubular article tensioning device for hosiery circular machines, for manufacture of socks and the like, characterized by the fact that it at least includes an article seizing and tensioning device or member, provided with an alternate motion, to effect an active tensioning stroke, in cooperation with at least another seizing member which may be active to effect a tensioning action dephased with respect to that of the first member, or only a retaining action of the article during the inactive return stroke of the first member; said first article seizing and tensioning member, which is connected to a unit alternately movable in the axial direction, being made in the active portion with an annular development, capable of diameter reductions by effect of resilient yieldings, consequently to its contact or its displacement with respect to a funnel wall wherein the article is developed.

According to one embodiment, an engaging member and particularly an engaging and tensioning member comprises an open resilient ring, similar to a piston ring for internal combustion engine pistons, which ring is capable of appreciable variations in diameter and thus of radial movements, when the member is reciprocated.

According to another embodiment, an engaging member and particularly an engaging and tensioning member is formed by a tubular sleeve, the outer wall of which serves as the active portion.

During the active stroke, the active portion formed by "ice the periphery of the open resilient ring or by the edge of the sleeve or other engaging or tensioning member 1 contacts the article being formed in cooperation with said funnel wall and is resiliently restricted sliding along the wall and engaging the article.

When provision is made for two alternately moved assemblies, the active stroke of one of the assemblies begins before the end of the active srtoke of the other assembly.

When a single alternately moved assembly is provided, the assembly being fitted with an engaging and tensioning device, the other engaging member acts as a retaining member, which may engage the article, cooperating with a flat or conical surface, to allow the advance of the article under the action of the tensioning member, and to prevent a return of the article towards the knitting formation zone.

The two engaging members may be both formed by resilient coaxial annular section members, having a different unstressed diameter and slightly spaced each other in the axial direction. A funnel member having a step between two lengths of conical wall is provided for reducing the difference between the two distances of the two article-engaging zones by the annular members with respect to the knitting formation zone. Only one of said members may be provided with an alternate motion"to operate the tensioning, and the other then being only a retaining member, or they may be both provided with an alternate motion.

The active end edge of a said resilient sleeve may be shaped and/or cut and/or serrated to aid the engaging action on the article.

An embodiment of a tensioning device in accordance with the invention will now be described, by way of example, with reference to the accompanying diagrammatic drawings, in which:

FIG. 1 is a longitudinal section of a circular knitting machine cylinder incorporating the tensioning device;

FIGS. 2 and 3 illustrate details of the operation of the tensioning device in two configurations of its active members;

FIG. 4 illustrates a modification of the embodiment of FIGS. 2 and 3;

FIG. 5 is a perspective view of a resilient annular member which can be incorporated in the modification of FIG.

FIG. 6 illustrates a detail of another embodiment;

FIGS. 7 and 8 similarly illustrate as FIG. 2 and 3, a modification of the embodiment of FIGS. 2 and 3 in two positions of the single active member required for tensioning, which is provided in this modification; and

FIG. 9 illustrates a further modification of the embodiment of FIGS. 2 and 3.

Referring to FIGS. 1 to 3, two members 1, 3 spaced apart on a common axis form a part of the machine and at the space I between the members the article is gradually knitted as it is formed, to be forwarded into the axial cavity of the member 1. In this embodiment a downwardly-directed draught is provided and a funnel member 7 is fast for rotation with the cylinder and thus has a rotational speed corresponding to that of the article being formed. The funnel member 7 has an appropriate profile with a relatively high slope, that is, with a relatively small angle a with respect to the cylinder axis. The member 7 may be driven by one of the rotary members of the needle cylinder, through a gear wheel or the like.

The member 3 has a vertically-extending tubular portion 3a, lying within stationary structure 10 of the machine.

Two tubular elements 12 and 14, one inside the other and both rotated by the member 3 are disposed in tubular portion 3a and are capable of relative sliding motion in the axial direction, both with respect to each other and with respect to the member 3, 3a. The tubular element can be coupled to the member 3a by a pin 16, which is housed in a longitudinal slot 14a of the tubular element 14. A radial arm 18, projecting from the tubular element 12 also engages in the slot 14a. A radial arm 20 extends from the element 14 and carries a roller 20a at a radial distance from the cylinder axis corresponding to the radial distance at which a roller 18a carried by the arm 18 is located. In practice, more than two arms may be pro vided which are symmetrically arranged around the cy1inder axis. The rollers 18a and 20a engage an annular cam 24 coaxial with the cylinder axis, and carried by the stationary structure 10, through the intermediary of screwadjusted supports 26. The rollers 18a and 20a are biased against the undulating cam profile by springs 28 and 30 respectively, which act between upper and lower flanges of the tubular elements 14 and 12 respectively.

Each of the two tubular elements 12 and 14 carries at the lower end an axially-extending resilient sleeve 32 and 34 respectively. The two sleeves are of resilient material such as natural or synthetic rubber, and each has an internal flange at the upper end for securing to the end flanges of the tubular elements 14 and 12. The attachment position is spaced from the tubular walls of the sleeves, so that the annular junction between the sleeve and its flange can deflect under stress. The lower edges 32a and 34a of the respective sleeves lie adjacent the conical portion of the funnel member 7, and co-operate therewith when the respective assembly 32, 14, or 34, 12 is lowered by the corresponding spring 28 or 30.

When one of the resilient sleeves is lowered, it engages the article M being formed between the conical portion of the member 7 and the same edge and forces the material downwardly in the direction of the arrow f of FIG. 2, the .resilient sleeve edge tending to get narrower. In FIG. 2 the edge 32a of the sleeve 32 is shown in action when lowered in the direction of the arrow f while the sleeve 34 is shown when inactive. In FIG. 3, instead of the edge 32a of the sleeve 32, the sleeve 34 is shown in action. During the lowering of a sleeve, the active edge thereof tends to narrow down in a uniform manner, partly also deforming the Wall of the corresponding sleeve, and uniformly forcing the sleeve to slide and thus tensioning it over the length between the contact zone of the active edge and the needles forming the article.

Before the start of the return stroke, that is, of the separation of the active edge of a sleeve, the active edge of the other sleeve will have become operative so as to ensure the continuity of the tensioning. The offset in the control of the two assemblies is determined by the angular position of the contact rollers 18a and 20a, in relation to the profile of the cam 24. For the purpose of approaching as close as possible to each other, the working zones of the edges of the two sleeves with respect to the working zone of the needles, by ensuring a certain interspace between the sleeves (so as to allow the deformation of the outer sleeve 32), there is provided a step between said two working zones of the edges of the sleeves, which enables the conical wall to be given a steep slope.

In case of wear of the sleeves 32 and 34, their position in the axial direction can be adjusted by means of adjustment means, which may be independent for the two axially-movable assemblies, or may effect simultaneous action on the two assemblies. These adjustment means may take the form of adjustable supports 26 for the cam 24.

The hereinbefore described tensioning device may be rendered inoperative by lifting the two assemblies and then the two sleeves with respect to the funnel member 7. For this purpose, a lever 36 pivoted at 37 on a stationary support and operable by a rod 38 is provided. The rod may be actuated by a working program means or schedule provided in the machine. The lever 36 acts to lift the tubular element 12 the flange of which con- .4 tacts and thus also raises the tubular element 14. This may be needed for certain stages of knitting of an article, for instance, for the formation of the heel of a sock or stocking. In this heel forming stage, and whenever a symmetrical tensioning is required, it is possible to use a previously suggested device including a member 39 with a lateral extension intended to engage the article asymmetrically for the tensioning. The member 39 is carried by a rod 40 capable of axial sliding motion controllable by program means.

In the drawing, the edges 32a and 34a are uniform and continuous, but may also be shaped with shoulders and annular grooves, with a rounded outermost periphery, with serrated or knurled surfaces for contacting the article, or longitudinal cuts or slits to form with the resilient material of the sleeves, flexible extensions to facilitate the centripetal deformation of the active edges.

The use of the working or operational members in the form of resilient sleeves as hereinbefore particularly described, makes the device inexpensive, not liable to jam during the use, unlikely to damage the article in the contact zone, that is, in the engagement zone and renders the replacement easy. The material of the sleeves may be rubber, synthetic elastomers, or resiliently flexible synthetic-resins.

In the modification illustrated in FIGS. 4 and 5, a conical stepped profile 41 similar to member 7 is provided. Two open resilient rings 42, 43, which are housed, in such a manner to vary their own diameters within certain limits, in annular grooves 44a and 45a of two cup-shaped members 44, 45 and co-operate with the profile 41. The members 44, 45 are rigid with the two tubular elements 14 and 12 respectively, to be provided with an alternate motion as in the previous embodiment. With this arrangement, the variations of diameter of the engaging members of the article M are obtained by effect of the resilient deformations capable of being imposed by the profile 41 on to the resilient rings 42, 43, which slide in the grooves 44a, 45a, respectively.

These resilient rings 42, 43 may be made in metal or other appropriate material and may have an outer profile shaped to engage the article during displacement in the direction of the arrow f and to slide Over the article during the return stroke. To this end the rings 42, 43 may have a profile as indicated in FIG. 6, with the lower outer edge projecting and serrated.

Also in this modification it is possible to obtain an alternative resilient traction by two members each of which resiliently reduces its own diameter along the frustoconical profiles of the member 41, similarly to the member 7.

Referring to the further modification illustrated in FIGS. 7 and 8, a funnel-like body 51 is provided similar to the member 7 or 41, along which the article M is formed. A resilient sleeve member 53 is similar to the sleeve 32, which with its lower edge cooperates with a conical wall of the member 51, so as to allow the displacement of the article in the direction of the arrow i but to prevent the return thereof in the opposite direction towards the knitting formation zone. The member 53 is not reciprocated and continuously cooperates with the member 51. A second sleeve member 55 is instead provided with reciprocatory motion according to the double arrow f to cooperate cyclically with the member 51 and effect the article tensioning and thus the advance of the article in the direction of the arrow f during the active stroke in the direction of the arrow i of FIG. 8, while during the return stroke (that is lifting stroke) the article M is retained by the cooperation of the member 53 and the member 51. The active edge 55a of the resilient sleeve member 55 will be shaped and contoured so as to eifect engagement during the active stroke indicated by the arrow i but to allow sliding during the stroke in the reverse direction. The funnel member 51 may have a stepped profile dividing the zones thereof cooperating with the sleeve 53 and with the sleeve 55.

According to the still further modification of FIG. 9, a conical member 61 is similar to the member 7, 41, or 51 of the previous examples. The conical member 61 has a flat portion 61a disposed directly inwardly of the annular knitting formation zone. The lower active edge of a pressing member 63, preferably in the form of a resilient sleeve, is biased against this portion 61a, and this pressing member 63 may be continuously so biased. It may be arranged to permit the sliding of the article M in the direction of the arrow f or it ma be operated to be cyclically raised during the advance phase for reciprocatory motion. The advance is effected by a resilient sleeve member 65, the edge 65:: of which may be resiliently restricted during the active tensioning stroke in the direction of the arrow f of FIG. 9. During the return stroke which takes place in the opposite direction to that indicated by the arrow f the member 65 has no tendency to pick-up of the article M and this remains retained by the pressing member 63 so as to prevent the return of the article again towards the knitting formation zone.

A provision may be made for a device similar to one of those described, but operating to tension the article upwardly instead of downwardly, so the article is delivered in the opposite sense. Return and pick-up means could then be provided to raise gradually or in a discontinuous manner the article upwardly, after passing the tensioning zone of the device.

What is claimed is:

1. In a device for tensioning knitted tubular fabric on a circular knitting machine,

an article engaging and tensioning member,

means for imparting to said tensioning member a reciprocatory motion including an active tensioning stroke,

at least one further tensioning member effective to provide a tensioning action substantially out-of-phase with respect to the tensioning action of the said tensioning member,

means defining a funnel through which knitted fabric passes, and

means defining on the said article engaging and tensioning member an annular section portion capable of yielding resiliently when said portion engages the fabric and presses it against said funnel.

2. A device according to claim 1, wherein said article engaging and tensioning member comprises a resilient split ring.

3. A device according to claim 1, wherein said annular section portion is of resilient elastomer material.

4. A device according to claim 1, wherein the tensioning members comprise coaxial hollow cylinders of different diameters and slightly radially spaced from one another.

5. A device according to claim 1, wherein the funnel member includes a step lying in a plane normal to the axis of the funnel and dividing the conical surface portion into two parts.

6. A device according to claim 3, wherein said annular section portion has an internal flange spaced from the part thereof which engages the fabric, means for securing the flange to the remainder of the article engaging and tensioning member, and a junction between the annular portion and the flange, said junction being spaced from the securing means.

7. A device according to claim 1, wherein the annular section portion is serrated to increase the engaging action on the fabric.

8. In a device for tensioning knitted tubular fabric on a circular knitting machine,

means defining a flat annular surface,

means defining an internal conical surface lying inwardly of said fiat annular surface,

an article tensioning means arranged to engage knitted fabric passing over the conical surface and thereby apply tension thereto,

means for slidingly engaging the knitted fabric continuously as it passes over the fiat surface, and means for reciprocating the tensioning means whereby the fabric is intermittently engaged and tensioned,

said means engaging the fabric over the flat surface acting to prevent reverse movement of the fabric when the tensioning means are spaced from the fabric.

9. In a device for tensioning knitted tubular fabric being formed on a circular knitting machine have a cylinder,

first and second assemblies each including a fabric-engaging annular resilient member,

a rigid tube carrying the resilient member,

a helical spring biasing the assembly in a given direction,

a cam-follower fast for rotation with the tube, and

an annular fixed cam with an undulating profile, said cam being engaged by the cam-follower and being co-axial with the cylinder,

the fabric-engaging annular resilient members being reciprocated into and out of engagement with fabric knitted on the cylinder by the respective cams and springs and being substantially out-of-phase with one another.

References Cited UNITED STATES PATENTS 2,017,082 10/1935 Warren 66153 2,345,698 4/1944 Bromley et a1 66-150 2,521,258 9/1950 Semotan 66-150 3,003,342 10/1961 Kent et al 66150 3,292,394 12/1966 Luchi 66--149 3,380,266 4/1968 Williamson et al. 66-150 FOREIGN PATENTS 1,030,208 3/1953 France.

868,487 2/ 1953 Germany.

918,320 2/1963 Great Britain.

W. CARTER REYNOLDS, Primary Examiner, 

